System design · Explainer

What is PAVA?

By Nigel Williams · Published 14 October 2026

A Public Address Voice Alarm (PAVA) system is one sound system that does two jobs on the same amplifiers, loudspeakers and cabling. Most of the time it carries everyday announcements, paging and background music. In an emergency it broadcasts spoken instructions, live or pre-recorded, and those take priority over everything else it is doing.

One system, two duties

The public address duty is what the system does almost all the time: "the shop will close in fifteen minutes", a call for a colleague, music in the background.

The voice alarm duty is what it does when it matters. When the fire detection system or an operator triggers it, the system stops the music and the paging and broadcasts the emergency message instead.

Because one set of equipment carries both duties, the whole system has to meet the requirements of the stricter one. A loudspeaker that plays music on 364 days of the year is still a life safety device on the 365th.

Why a voice message rather than a bell

A sounder can only tell people that something is wrong. A spoken message can tell them what is happening and what to do. It can also tell different parts of a building different things at the same time: leave now on one floor, stand by on the next. That is what makes a phased evacuation of a large building workable.

What the emergency duty adds

• It watches itself. The system monitors its amplifiers, loudspeaker circuits and power supplies and reports a fault, so a failure is found when it happens rather than at the next emergency.
• It keeps running without mains power. Standby batteries keep it working through a power cut: at least 24 hours of standby followed by at least 30 minutes of full emergency broadcast (BS 5839-8:2023, Clause 25.3.5 a)).
• Emergency messages come first. They override music and paging, zone by zone.
• The equipment is made for the job. Control and indicating equipment is made to BS EN 54-16, and loudspeakers to BS EN 54-24.

PAVA, PA/VA and "PA system"

"Public Address Voice Alarm" names one system doing both duties, which is what PAVA means. "Public address and voice alarm" reads as two systems joined together, and is better written PA/VA when that is genuinely what is installed.

"PA system" on its own describes the everyday duty only. A building's PA system and its PAVA system can look identical in a ceiling; only one of them is designed, powered and maintained to work in an emergency.

Which standard applies

Venues within scope of the Terrorism (Protection of Premises) Act 2025, known as Martyn's Law, also need to think about how they would tell people what to do in an attack. The Martyn's Law guide covers what that means for an existing system.

Looking after one

Three routines keep a PAVA system ready:

1. A weekly test, managed by the person responsible for the premises, so that staff and some of the public hear the emergency message (BS 5839-8:2023, Clause 39.1).
2. Servicing at least every six months by a competent person (Clause 40.1).
3. An annual listening check in every loudspeaker zone, to confirm announcements can be understood throughout (Clause 40.2(j)).

The standby batteries are the part most often sized wrongly. The battery series works through the calculation, and the battery calculator does it for you.

Read next

• 100 V line explained: why the amplifier's power reaches the loudspeaker and not the cable.
• BS 5839-8, in our own words.
• Not sure where your system stands? The system health check takes a few minutes.